I've just discovered using radeon-profile that my AMD Radeon R5 M330 is limited to 750MHz core/1000MHz memory on Ubuntu, but since that's too low (Core should be limited to 1030MHz) I want to increase the limit. I have tried some methods which include adding/modifying files in /sys/class/drm/card1/device/, but even with root access (tried both sudo and root terminal using sudo su) it says permission denied. I haven't found any other methods.

I am not trying to overclock here because the OEM set the core clock speed for the GPU on Windows to 1030MHz, so I just want to set the limit on Ubuntu to what it's supposed to be.

TL;DR: How to change the clock speed limit for the core/memory of an AMD Radeon GPU?

Note: I'm using open-source driver radeon with the padoka PPA added.

2 Answers 2


radeon-profile: tool for changing profiles and monitoring some GPU parameters

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Might wanna ask here: https://www.phoronix.com/forums/forum/linux-graphics-x-org-drivers/open-source-amd-linux/37384-radeon-profile-tool-for-changing-profiles-and-monitoring-some-gpu-parameters/page14?83602-radeon-profile-tool-for-changing-profiles-and-monitoring-some-GPU-parameters=

The developer of the tool has been active at that forum.

  • This should be a comment
    – Tooniis
    Jan 2, 2018 at 2:37
  • This tool is what I am using to determine the maximum frequencies of my GPU, and I know that it cannot change them with the radeon driver.
    – Tooniis
    Jan 2, 2018 at 6:08
  • 1
    > This should be a comment – Tooniis @Tooniis I agree. However I wasn't able to add a 1st comment apparently because of my reputation or lack thereof in this forum.
    – SD Allen
    Jan 2, 2018 at 19:45
  • 1
    since no one gave a good answer, and not to waste rep, I guess I will award you the bounty to be able to comment on questions to get more information and be able to answer more questions.
    – Tooniis
    Jan 8, 2018 at 8:20
  • 1
    Thanks! I'm not an expert, nor am I a beginner to Linux/Unix, simply just not used to using this format. Old school. I'll adapt though.
    – SD Allen
    Jan 9, 2018 at 11:35

I was able to achieve that with the help of this tutorial:


After downloading the Linux kernel source, I modified line 2985 of /linux-4.13.0/drivers/gpu/drm/radeon/si_dpm.c from max_sclk = 75000; to max_sclk = 103000;, then rebuilt, installed the modified kernel, and rebooted my machine.

However, it includes rebuilding the whole Linux kernel and installing it, which if not done properly, it can cause the OS to break and maybe not even boot up. Also it takes a lot of time, as it took almost an hour to compile on my machine, so it is not an ideal solution.

Warning: Do this only if you know what you are doing, because you might break your OS, or even damage your hardware.

Another Warning: You should set max_sclk to the clock frequency set by your machine's OEM or lower, unless you know what you are doing.

Update: The fix above is a hack. The proper fix would be to check first if your GPU is stable at the maximum core clock, then remove your GPU's ID from the list like in this patch, and submit your patch to the mailing list for it to be merged upstream.

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